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Solid State Quantum Information
Solid State Quantum Information
Quantum Defect Laboratory - UW (Current project)
Impurities in solid-state crystals with optical access have received a lot of attention as potential spin-qubit candidates for applications in quantum computation and communication. Advantageous properties include their potential for scalable device integration and spin-photon entanglement. Efficient entanglement generation and long spin-coherence times are paramount for photon-based applications, such as measurement-based quantum computation and long-range quantum communication. Defects such as nitrogen vacancy centers in diamond, and various defects in silicon (such as phosphorous) have demonstrated long spin-coherence times but are challenged by poor radiative efficiency, optical inhomogeneity, and spectral diffusion. On the other hand, defect systems in III-V semiconductors, such as donors and quantum dots have demonstrated efficient optical transitions, spin control and spin read-out, but lack a spin-free host that can significantly limit coherence times.
The shallow neutral donor D0 in zinc oxide (ZnO) , a direct band-gap semiconductor, is efficiently optically coupled to the donor-bound exciton D0X. Ensemble studies in unintentionally doped natural ZnO crystals showcase a remarkable near lifetime-limited linewidth (O(1)) and large optical depth (up to 300). Additionally, spin-relaxation times of 0.5 s, spin-echo coherence times of 50 μs and the potential for nuclear spin-free host with isotope purification, make D0 in ZnO an attractive spin-qubit candidate for photon-based quantum technologies. We have performed all-optical measurements on the spin properties as a function of magnetic field, temperature, and excitation energy to better understand the relaxation mechanisms.
Working with collaborators that help us implant donors and mill ZnO via plasma-enhanced focused ion beam milling, we aim to control the formation of donors and integrate nanophotonic structures. Our ultimate goal is to use ZnO donors in quantum memory and entanglement protocols with ytterbium ions for quantum communication applications.
My job is to design and conduct steady-state and time-dependent photoluminescence and transmission spectroscopy experiments to determine the optical and spin properties of the qubit system. This extends from coding (mainly in Python), integrating, and automating our equipment to perform a new experiment to analyzing and interpreting data and the physical mechanisms behind my observations and frequently presenting the results to my peers.
Here you can find my data analysis repository and a steady state Hamiltonian solver. Related publications to which I contributed can be found on the publications page.
Particle Physics and Detector Design
Particle Physics and Detector Design
With the new high luminosity large hadron collider (HL-LHC) at the European Council for Nuclear Research (CERN), the charged particle detection rate would be too fast for current technologies, which could lead to high background signal due to pileup. Detectors with faster response are paramount at keeping the background low and allow for better timing resolution. A new type of of Micro-Mesh Pattern Gaseous Structure (MicroMeGaS) was designed and tested by the PICOSEC team of the RD51 collaboration.
The detector consists of three main parts; a Cherenkov Radiator, a photocathode, and a two-stage signal amplifier. When a charged particle passes through, the Cherenkov radiator produces UV photons. The photons are then absorbed at the photocathode and partially convert to electrons. These electrons are subsequently preamplified and then amplified in the two high-field drift stages, and finally induce a signal which is measured between the anode and the mesh. This detector yields 25 ps timing for 150 GeV muons and 76 ps for single photons.
My job as an undergraduate researcher was to analyze the detector's output signal and retrieve its timing resolution utilizing the C++ libraries Root CERN. I also attempted to apply various FFT-based filters to reduce the signal noise and increase the timing resolution. All proposed methods yielded similar timing resolution.
As a post-back researcher, I simulated the detector response and designed an ultra-fast calorimeter using Geant4 (C++-based). The calorimeter simulation code can be found on my github.
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